Bending apparatus



1956 K. R. NEER 2,769,477

BENDING APPARATUS Filed April 17. 1952 3 Sheets-Sheet l ATTORNEYS Nov.6, 1956 K. R. NEER BENDING APPARATUS 5 Sheeis-Sheet 2 Filed April 17,1952 INVENTOR R. NEER KENNETH ATTORNEYS Nov. 6, 1956 Filed April 17.1952 K. R. NEER 2,769,477 BENDING APPARATUS 3 Sheets-Sheet 3 BY M ,w W

ATTORNEYS United States Patent 6 BENDING APPARATUS Kenneth R. Neer, SanDiego, Calif., assigor to Solar Aircraft Company, San Diego, Calif., acorporation of California Application April 17, 1952, Serial No. 282,861

7 Claims. (Cl. 153-54) This invention relates to apparatus for formingblanks of sheet material and more particularly to apparatus for formingprecut fiat sheet metal blanks into arcuate shapes, especiallycylinders.

it has been found that the apparatus of the present invention haveparticular utility in connection with the manufacture of relatively thinwalled bellows and similar expansible convoluted units. Such units arenow commonly made from cylindrical blanks of thin gauge which areconvoluted or corrugated by a number or" well known methods.

Considerable difficulty has been experienced in the past in themanufacture of cylindrical blanks at reasonable expense which aresuitable for use in bellows forming operations. It has been commonpractice to employ Buffalo rolls and similar apparatus for this purpose.However, the product of apparatus of this type has an unrolled portionat its opposite edges which must be trimmed before the bent workpiececan be welded to form a complete cylinder. As a consequence, theformation of cylinders by this practice inevitably entails considerablewastage of materials.

More important is the increased labor cost of the additional trimmingstep which must be carefuily manually performed to insure the productionof cylinders which meet exact size requirements and have the necessaryparallelism between their opposite edges which are to be welded.

In partial solution to these problems it has been pr posed to bend asheet metal blank over a roll of predetermined size as shown, forexample, in Patent 2,454,- 282. While this method eliminates the wastagepro duced by the Buffalo rolls, it introduces other costs which off-setthis advantage. For example, in apparatus of this kind the formingrolls, which are relatively expensive, must be replaced to permit theslightest change of diameter of the formed cylinder. Further, apparatusof this kind is inherently incapable of performing a continuous process.That is, this apparatus must he stopped after each forming operation topermit the removal of the formed cylinder before the next work blank canbe formed.

In accordance with the present invention, fiat workpieces are formed asrequired by being subjected to the action of a resilient deformablerotating roller and a relatively stationary forming implement, thelatter being maintained in deforming pressure contact with the resilientsurface of the roller.

Despite the simplicity of the apparatus, it provides for the automaticfeeding of work blanks to the work forming station and for the automaticdelivery of one or a series of completely formed arcuate shapes readyfor welding.

Accordingly, it is the primary purpose and object of the presentinvention to provide novel apparatus for deforming one or a series ofsheet metal blanks into arcuate shapes'at lower cost and higher speedthan heretofore possible.

It is a further object to provide novel apparatus of this kind whichmay, by means of simple adjustment and without replacement of parts, beutilized for the production of sheet metal cylinders of Widely varyingprecisely controlled diameters.

It is an additional object to provide novel apparatus for forming sheetmetal cylinders in which sheet metal blanks, precut to exact size, areformed as desired over their entire surface and are automaticallydelivered ready for Welding.

It is also an object of the present invention to provide novel apparatusfor deforming sheet metal blanks into arcuate shapes which comprises aminimum number of structurally rugged parts compactly arranged forutilization as an attachment for a standard metal working lathe.

It is a further object of this invention to provide apparatus forbending a thin sheet metal blank into a cylinder or like shape having acontinuously curved surface wherein the blank is fed into a forming passdefined by a resiliently surfaced roller and a relatively stationaryedge extending along the roll.

Further objects and advantages will become apparent as the descriptionproceeds in connection with the accompanying drawings in which:

Figure 1 is an end elevation ofa metal forming apparatus constructed inaccordance with the present invention shown mounted on a lathe bed;

Figure 2 is a side elevation of the apparatus of Figure 1 With partsbroken away and in section to illustrate details; 7

Figure 3 is a top plan view of the apparatus of Figures 1 and 2;

Figure 4 is a perspective view of one of the forming elements of theapparatus of Figure 1; and

Figures 5, 6, 7 and 8 illustrate diagrammatically the several stages inthe formation of a metal cylinder in accordance with the presentinvention.

The metal forming apparatus will be shown and described as an attachmentfor a standard metal working lathe since experience has shown that,where the size of the workpiece permits, minimum production costs may beachieved by the utilization of the apparatus in this manner. However, itis within the scope of the invention to provide a complete unitincluding a drive mechanism to be utilized independently of existingapparatus such as lathes or other powered shop equipment.

With continuing reference to the drawings, a power operated lathe head,having the usual threaded spindle it is shown diagrammatically at 12.The details of the lathe form no part of the present invention and thehead may take any conventional form.

In accordance with conventional practice the lathe head 12 is rigidlysecured to a lathe bed 13 provided at its upper surface with the usualguide rails 14 and 15.

Mounted for sliding movement on the rails 14 and 15 is a fiathorizontally arranged stand 16 having suitable grooves in its lowersurface in register with the ridges of the respective guide rails. Thestand 16 may be secured in adjusted position with respect to the lathebed 13 by suitable clamps 17. Bolts 19 extend through the respectiveclamps and may be adjustably threaded into the stand 16 to produce therequired clamping or locking action.

As best shown in Figure 2, a roller 18 comprising a metallic body 20 towhich a layer 22 of rubber or similar resilient material, is vulcanized.In a typical example where the roll body is 2 /2" in diameter, a rubberlayer having a hardness of 40 (Shore) and a thickness of issatisfactory. The roll body 20 is provided at one end with a recess 24having threads which match those of the lathe spindle 10. At itsopposite end the metallic roll body is provided with a stub shaftextension 26 adapted to be rotatably received in a bearing 28 mounted inan upright 30, a flanged portion 32 of which is secured to the stand 16by means of bolts 34. The roll body is provided with four spacedrecesses 36 adapted to receive a suitable tool for tightening the rollon the lathe spindle.

A fiat base member 40 having opposite lateral flanges 42 and 44 isguided for movement on the smooth upper surface of the stand 16 in adirection normal to the axis of the roller 18 in opposed gib plates 46and 48, re-

spectively, which are secured to the upper surface of stand 16 atopposite sides of the base member 48 by a plurality of bolts 50.Sufficient clearance is provided between the cooperating faces of thegib plates and the flanges of the base member 40 so that the latter mayslide freely in the former which thus act merely as guideways. Attachedto the opposite ends of the member 40 as by bolts 52 and 54,respectively, are vertically extending frame members 56 and 58. Themembers 56 and 58 are of generally the same configuration, the member58, however, being shorter than the member 56. An upper base member 60extends between and is secured to the upper edges of the verticalsupport members 56 and 58 by bolts 62 and 64, respectively, the member60 having notches to accommodate the upper edges of the support members56 and 58 to dispose the upper surface of the member 60 at an angle withrespect to the stand 16.

Rigidly secured to the upper sloping surface of the upper base member 60by bolts 65 is .a contour'block 66.;.As best shown in Figure 4 thecontour block 66 comprises rectangular supporting section 70substantially coextensive with the upper base block 60. The contourblock 66 also includes a work guiding and forming section 72, the'bottomsurface of which is an extension of the bottom surface of section 70 andthe upper surface of which is inclined downwardly with respect to theupper surface of the section 70 so that the section 72 is wedge shapedterminating at its forward seide in a relatively narrow work formingedge 74 normally parallel to, that is, making an angle of zero degreeswith the axis of roller 18. As hereinafter explained, edge 74 may bedisposed at an angle other than zero degrees with respect to the axis ofroller 18. The forming edge 74 of the contour block is illustrated inenlarged section in Figure 5, 6, 7 and 8.

As thereshown the forming edge 74 is disposed at an angle ofapproximately 10 with respect to a plane normal to the lower surface ofthe contour block 66 so that the juncture between the upper surface ofthe contour block 72 and the forming edge 74 constitutes a relativelysharp edge, in practice having a radius of /9,2 of an inch where theroller has the above-described dimensions. Opposite the rearward orupper edge of the section 72 of the contour block an idler roll isrotatably mounted on a shaft 81 mounted at'its opposite ends in lugs 82and 84 suitably attached to the section 72. The lugs are provided withslots in which the opposite ends of the roll shaft are received foradjustment to and away from the section 72. The roll may be locked inadjusted position by nuts 85 threaded onto the roll shaft.

' An endless belt 86 of canvas, or similar flexible, tough material,passes around the section 72 over the front forming edge.74 and over theroller 80 for a purpose to appear. The'support of the side of thecontour block adjacent the lathe head is provided by a bracket 88secured by bolts 90 to the lathe head proper. An adjusting screw 92extends adjustably upward through the block 88 and its upper end bearson a lug '94 welded to the side of the contour block 66. The free end ofthe block 88 is provided with an upwardly extending arm 96,'the

upper end of which extends above the upper surface of the contour blocksection 72 to guide the canvas belt 86 on the contour block.

As stated .abovethe base member 40, on which the contour block assemblyis mounted, is slidably movable in a direction normal to the axis of theroller 18. The adjusted positionof the entire contour block assembly maybe determined by an adjusting screw 98 which extends freely through thesupport 56 and'is threadedly received in an upstanding arm attached tothe stand 16 by means of bolts 102 A lock nut 104 is provided on theadjusting screw 98 to lock the contour block in its adjusted position.Movement of the contour block to the right, as seen in Figure 1, iseffected by turning the screw 98 into the arm ltltiurging a shoulder ofscrew 98 against the block 56. Movement of the contour block to the leftis efiected by threading screw 98 out of arm 106 urging a pin 106'whichextends through the inner reduced end of the screw 98' against the innerside of block 56. Due to the provision ofthe heavy gib plates 48 theforming edge 74 at the forward end of the contour block will remain inconstant parallelism with the axis of the roller 18.

A suitable guard or shield 126, which-is coextensive with the roller 18,is secured to the'upper surface of the portion 70 of the contour blockas by screws 128. It will be noted that there is substantial clearancebetween the lower edge of the guard 126 and'the upper surface of thecanvas belt 86 so that a workpiece may pass freely therebetween. V

The mechanism above described may be readied for operation by adjustingthe forming edge 74 of the'contour block so that it is in pressureforming contact with the resilient surface of the roller to deform theresilient surface to the extent required to perform the necessarybending operation. A precut sheet metal blankis then placed on thecanvas belt 86 with its leading edge in exact parallelism with the axisof roller 18. The lathe.

cause of the pressure contact between the canvas belt and V the surfaceof the roller 18 the former will be caused to pass around thecontour'block in a clockwise direction as viewed in Figure 1, thusdrawing the workpiece between the forming edge 74 and the. surface ofthe roller.

The workpiece is initially bent as shown in Figure 5. The bendingoperation then continues until the leading edge of the workpiececontacts, the belt 86 as shown in Figure 6 at which time the leadingedge of the work blank may be carried away from the axis of the roller18 to the point shown in Figure 7. However, experience has shown thatthis action does not continue to the point where the work blank isstressed beyond its elastic limit.

On the contrary, the forming operation progresses to the point shown inFigure 8 where the leading edge of the work blank is no longer carriedby the belt 86, The

'forming operation is then continued to form the work The blank springsinto remedy a temporary oversize or undersize condition caused by wearof the componentsora change 1n resiliency of the rubber layer on theroller 18.

It is also to be particularly noted that 'at the completion of theforming operation the finished workpiece drops away from the mechanismpermitting the production of a series of cylinders in rapid sequence asopposed to presently known apparatus of this type. The above describedapparatus is also capable tion. For example, by mounting the roller 18with a slight eccentricity, the pressure between the forming edge 74 andthe outer resilient surface of the roll will of bending. sheet metalinto shapes other'than those having circular sec-' be varied during theforming operation thus changing the rate of bending and producing atubular workpiece having an elliptical or other non-circular section.

Also, by disposing the forming edge 74 of the contour block at a slightpredetermined angle with respect to the axis of the roller 18, theforming pressure and accordingly the rate of bending will be varieduniformly along the length of the workpiece thus producing conicalshapes. The predetermined angle may be zero degrees in which case theedge 74 would be parallel to the axis of roller 18 as hereinabovedescribed.

Thus the invention attains the objects above stated and providesextremely simple, versatile and inexpensive apparatus capable ofproducing tubular workpieces of varying size and section at low cost andhigh speed.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. A mechanism for forming bendable material comprising a movableelement having a deformable portion, a relatively stationary memberhaving a rigid forming edge disposed in deforming pressure contact withsaid deformable portion, and means movably mounted on said member andmovable with and to facilitate passage of a sheet of said bendablematerial between said element and said forming edge of said relativelystationary member to deform said material into an arcuate shape.

2. The mechanism of claim 1 together with means to adjust the contactpressure between said forming edge and said deformable portion to varythe deformation of said material.

3. In a sheet metal bending apparatus, a member having a fixed edge, aconveyor sheet mounted to move over said edge with a blank thereon, anda resiliently surfaced member mounted to engage the side of the blankopposite said conveyor under pressure and move therewith past said edge,

4. A mechanism for forming sheet material comprising a roller having adeformable outer surface, a substantially flat contour block having aforming edge substantially parallel to the axis of said roller, meansmounting said block to dispose said forming edge a distance from theaxis of said roll less than the normal radius of said roller, and meansmovably mounted between said sheet and said block to faciiitate feedingsaid sheet material over said contour block between said forming edgeand said roller to deform said material into an arcuate shape.

5. A metal forming attachment for a lathe having a driven spindle and abed provided with guide-ways, comprising, a stand adapted to besupported on said guideways; means on said stand rotatably supportingone end of a deformable roller, the other end of said roller beingsupported on said spindle for rotation therewith; a contour block havinga substantially straight forming edge; means on said stand forsupporting said block with said forming edge in deforming pressurecontact with the surface of said roller, whereby when said roller isrotated a work blank will be drawn between said roller and said formingedge to deform said work blank into an arcuate shape, and means to movesaid forming edge in a direction normal to the axis of said roller tovary the deformation of said work blank.

6. A mechanism for forming bendable sheet material comprising a rollerhaving a deformable surface, a relatively stationary contour blockhaving a substantially straight forming edge disposed in deformingpressure contact with said roller, an endless carrier encircling saidcontour block and adapted to pass thereover in a direction normal to theaxis of said roller, and means to rotate said roller whereby a sheet ofsaid material will be drawn between said roller and the forming edge ofsaid guide block to deform said material into an arcuate shape.

7. In a sheet metal bending apparatus, a member having a fixed edge,means movably mounted on said member adapted to move over said edge witha work blank thereon, and a member having a deformable surface mountedto engage the side of the work blank opposite said edge under pressureand move therewith past said edge to bend said work blank.

References Cited in the file of this patent UNITED STATES PATENTS590,857 Potter Sept. 28, 1897 711,180 Seymour Oct. 14, 1902 1,017,815Sharp Feb. 20, 1912 1,126,982 Goss Feb. 2, 1915 2,196,076 Moran Apr. 2,1940 2,454,282 Johnson Nov. 23, 1948 2,609,191 Foster Sept. 2, 19522,609,192 Lermont Sept. 2, 1952

